Help with total CPU utilization?

I use the following query to poll for CPU usage on my ESX server via SNMP. It works fine. However, what I’d like to do is have a query that could take all 12 values (esxi-cpuload01 through 012) and average them, delivering a single line graph representing overall CPU usage.

I’m not at all sure how to do that - any help would be great!

SELECT mean(“esxi-cpuload01”) FROM “system” WHERE (“agent_host” = ‘’) AND timeFilter GROUP BY time(__interval) fill(null)